My last period started on the 26.12.11 and I have a very regular 27 day cycle so I am due on again on the 21.1.12. I had unprotected sex with my boyfriend from 27.12.11 till the 4th January 2012 when he returned to work. Is there a possibility I may be pregnant? I feel bloated in the stomach and feel moody, but this may be because I'm due on in a week? I have 2 children already.
Thanks

Of course. You have two children. Any time you have sex, protected or otherwise, there's a chance of pregnancy.

Wait and then try home pregnancy testing.